This invention relates to balers for forming bales from a crop or harvest products gathered from the ground and more particularly for balers for forming cylindrical bales of such products.
One conventional type of such a baler for forming large diameter cylindrical or round bales is tractor drawn and operates to form a bale by picking up harvested products from a windrow as with a pickup mechanism as the baler is advanced over the field. The mechanism transfers the products rearwardly into an opening leading into a bale-forming chamber in which the products are rolled up into a bale between an upper conveyor and a lower conveyor, each being formed of parallel bands or belts. The bale is rotated between the belts about a horizontal axis as it is formed. Such a baler is exemplified in U.S. Pat. No. 3,931,702. Other types of belt conveyor arrangements for forming a bale forming chamber are also known and are exemplified in U.S. Pat. Nos. 4,182,101, 4,121,513, and 4,252,057.
One well known problem associated with the use of such balers results from the fact that the windrow is often narrower than the pickup mechanism and the opening to the bale forming chamber which extend transversely of the windrow. Consequently, if the same alignment of the baler with the windrow is maintained, the harvest products are fed into only a portion of the width of the chamber opening. This, in turn, results in the formation of a bale with a nonuniform diameter. For example, if a larger amount of the harvested products is fed into the central portion of the chamber opening a barrel-shaped bale is formed. For efficient and trouble-free operation of such balers, the formation of a bale of uniform diameter is highly desirable.
One well known solution to this problem is for the driver of the tractor pulling the baler to steer the tractor so that the baler follows a zigzag or sinusoidal path with lateral transversing in relation to the windrow. In this way the presentation of the windrow to the pickup is progressively displaced across the pickup width, thereby producing a bale of uniform cross-sectional diameter. Another disadvantage associated with the requirement to drive in a zigzag pattern is that the driver is required to pay close attention to his driving pattern and the resulting configuration of the baler so that a bale of uniform diameter is formed. To accomplish this, the drive must be frequently looking to the rear.
To avoid the need for a sinusoidal driving pattern, it is proposed in U.S. Pat. No. 4,065,914 to mount a hydraulic cylinder between the frame of the baler and a tongue pivotally mounted at one end to the baler frame and pivotally connectible to the tractor drawbar at the other. The driver can steer the baler by operating the hydraulic cylinder to cause the baler to pivot and undergo a zigzag or sinusoidal movement while the tractor advances along a linear path of travel. Nevertheless, with such an arrangement, the driver still has to pay constant attention to the steering of the tractor, the baler and the bale being formed in the baler in order to form a bale of substantially uniform diameter. It is clear that both systems require a reasonably skilled operator to produce uniform diameter bales and will lead to operator fatigue.
Accordingly, it is an object of this invention to provide an improved cylindrical baler with an automatically actuated steering mechanism which simplifies the bale-forming process, reduces operator fatigue, enables a more exact monitoring of the bale shaped during formation and relies less on the experience of the operator for formation of bales of substantially uniform diameter.
Another object of the invention is to provide an improved baler which enables formation of a cylindrical bale with a more uniform shape and density.